Zoning is a local function. It is not the place of the Commonwealth to step on one of the few areas of governance with respect to which the Dillon rule affords broad discretion to localities. Most localities where there is any demand for ADUs permit them without undue administrative burden. Development patterns vary from locality to locality, as do preferences. The principle of subsidiarity should apply here. Let the lowest level of government, closest to the actual residents, make these determinations.